The Menlo Park, California-based company, which gets a vast majority of its revenue from advertising, told Bloomberg that it was still investigating the overall impact "including the possibility of refunds for advertisers". Their outage map for Facebook showed a surge in reports in the Northeast from Washington, D.C. through NY, though a cursory search of the Twitter free-for-all on the topic indicates the reach is well beyond the greater metropolitan areas.

Media reports earlier said millions of users were affected, and thousands took to Twitter on Wednesday and Thursday to complain under the hashtag #facebookdown.

As of Thursday, downdetector.com showed 37 percent of problems Thursday morning related to log-in; 32 percent with loading the newsfeed; and 30 percent a total blackout. Reuters was not immediately able to verify those claims and the company declined to comment beyond the statement on resumption of services. The federal investigation is the latest bad news coming from the company's data privacy scandals. Amazon was reportedly allowed to see user contact information. It's believed to be the biggest interruption ever suffered by the social network.